CONSTRUCTION OF HOT-HOUSES.-NO. 2. 
121 
CONSTRUCTION OF HOT-HOUSES.—No. 2. 
Polmaise Heating .—There are various 
modes of constructing hot-houses with 
the view of affording the most efficient 
means of supplying such heat and venti- 
1 lation as will produce the most perfect and 
healthful cultivation, and this to be ac¬ 
complished with the least labor and cost. 
It would seem that, from some well-tried 
experiments made in Great Britain during 
the last two or three years, in no system 
has there ever been so much heat diffused, 
attended with healthy ventilation, with so 
small an expenditure for fuel, or at a less 
cost in its original construction, as that 
denominated “ Polmaise,” the name of the 
place where it originated. We do not wish 
to be understood to say, however, that we 
disparage the mode of heating by hot 
water, but, on the contrary, are aware of 
Polmaise Plan—and Elevation of a Hot-House.— Fig. 27. 
its excellence and advantages; and we think it would 
be very unwise in any one having a good hot-water 
apparatus to pull it down for the sake of substi¬ 
tuting the Polmaise. “ Let well enough alone,” is 
an excellent maxim; but do not allow it always to 
prevent striving to do better. 
Description .—The plan of the house, A, shows 
the cold-air entrances, cold-air drains, hot-air cham¬ 
ber, and entrances for air into the house, with fur¬ 
nace, chimney, and direction of currents ; a, a, cold- 
air entrances, covered at pleasure with horizontal 
lids outside of the house (these entrances, in cold 
weather, are generally kept closed, being only oc¬ 
casionally opened); b, b, cold-air drains, covered 
at pleasure with sliding covers, made of slate ; c, e, 
entrances for hot air into the house, which may 
